that includes an operating system, middleware and key applications. • Android OS is divided into five sections • Applications: This is where applications to be installed are written. E.g. Games, Browser etc. • Application Framework: This layer provides many higher-level services to applications in the form of Java classes. • Android Runtime: This section provides a key component called Dalvik Virtual Machine. Dalvik VM enables every android application to run in its own process, with its own instance of the Dalvik VM. Dalvik VM is optimised to run on slow CPU, low RAM, low power devices. It runs .dex files and not .class nor .jar • Libraries: e.g. SQLite database, repository for storage and sharing of application. • Linux Kernel : it provides basic system functionality e.g. process management, device management etc.
*Not relevant in the ecosystem* • Android 1.5 Cupcake *Not relevant in the ecosystem* • Android 1.6 Donut *Not relevant in the ecosystem* • Android 2.0/2.1 Eclair *Not relevant in the ecosystem* • Android 2.2.x Froyo *Not too relevant in the ecosystem* • Android 2.3.x Gingerbread *Still somewhat relevant in the ecosystem* • Android 3. x Honeycomb *Not relevant in the ecosystem* • Android 4.0.x Ice Cream Sandwich *Still quite relevant in the ecosystem*
of Java • Latest Java Development Kit (JDK) : Android Apps are developed using Java. http://www.oracle.com/technetwork/java/javase/downloads/inde x.html • Eclipse Integrated Development Environment (IDE) https://www.eclipse.org/downloads/ or any other suitable IDE. • Android SDK http://developer.android.com • ADT Tools for Eclipse (via Internet)
of user interface. • Views: UI elements that are drawn onscreen. They are responsible for event handling e.g. ContextMenu, Menu etc. • Widgets: They are more advanced UI elements e.g Button, CheckBox, ImageView etc. • Layouts: View hierarchies that control screen format and appearance of the views.
of an action it needs to perform. They are used to start activities and to communicate among various parts of the android system. • Resources: External elements such as strings, drawables and constants • Manifest: Configuration file for the application.
and its child Views. Android supports different default layout managers. To get a desired layout, there are some few terms you would come across. ✔ android:layout_width defines the width of the widget. ✔ android:layout_heigth defines the height of the widget. ✔ match_parent tells the application to maximize the widget in its parent. ✔ wrap_content tells the layout to allocate the minimum amount so that the widget is rendered correctly.
a number of functionalities in android. To create spectacular apps, you should make use of them. • Touchscreen • GPS • Accelerometer • Internet • Audio and Video support • Contacts • Security • Google APIs
the framework API revision offered by a version of the android platform. ✔ It lets the android platform describe the maximum framework API revision that it supports. ✔ It lets applications describe the framework API revision that they require. ✔ It lets the system negotiate the installation of applications on the user’s device such that version-incompatible are not installed. You can catch more gist on API levels here
to consider keeping it simple. Nobody likes a complex-for-nothing application. I encourage drawing mock-ups ( a visual representation of how you want the application to look like), flow charts ( a step-by-step approach to achieving your goal) as one of the first steps before jumping on your IDE. You will need to step up your UI/UX game to ‘wow’ your users.
friend • Get familiar with android developers’ site • Read documentations before using any API • Join forums that will help. One of the most popular is stackoverflow • Get close to the ‘gurus’- they have a lot to offer. • Read books that will help.
objects referred to in a particular file. ✔ android:versionCode must be an integer. You typically start from ‘1’ and increase the value by one if you roll-out a new version of your application. ✔ android:versionName is what the users see. It can be any string. ✔ android:minSdkVersion defines the minimum version of android your applicaton works on. A user cannot install your application on a device with a lower API level than specified in this attribute. ✔ android:targetSdkVersion specifies the version on which you tested and developed. It is a good practice to always set this to the latest Android API version.
✔ <activity> tag defines an activity component. ✔ android:name="android.intent.action.MAIN" can be started and the category ✔ android:name="android.intent.category.LAUNCHER“ parameter tells the Android system to add the activity to the launcher.